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Hanging joist on concrete walls

Paperman

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Feb 19, 2014
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On the shore of LK Michigan
Can I securely hang joist on a CMU wall? I have an room 20x70 with 17' ceilings Id like to separate into 2 levels. I could stud wall inside and set the joist but is there an option to hang them from the wall?
 
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The Tool Tyrant

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You can bolt a ledger to the CMU and then hang the joists. Is the block grouted solid?

^^ Exactly. If you want to be safe, (rather than sorry) You would be smart to consult a structural engineer and discuss what you'll be loading on the deck, so that he can calc. what size ledger material to use, along with bolting specs.
 

Hilltopmasonry

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Oct 12, 2015
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There are ways of doing it however you need to know what the integrity of your wall is because there are block walls that are incredibly strong and there are other block walls that are incredibly weak

Another option is to cut pigeon holes in the block wall and shove the floor joist in the holes so they are sitting on the wall instead of hanging on them.

That’s basically how all of the three flats in Chicago are built where they build the walls up one floor then put a deck on then build the walls up another floor, then put a deck on


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theoldwizard1

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SE MI
You can bolt a ledger to the CMU and then hang the joists. Is the block grouted solid?

^^ Exactly. If you want to be safe, (rather than sorry) You would be smart to consult a structural engineer and discuss what you'll be loading on the deck, so that he can calc. what size ledger material to use, along with bolting specs.

I would NEVER trust that type of connection, especially on a CMU, unless it has structural engineers stamp on it. If you want to use a ledger, support it with properly spaced 2x4 or 2x6.

They do make special joist hangers that you can insert into the mortar while the wall is being built. They also make top flange joist hangers that go OVER the top of the wall.
 
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theoldwizard1

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Another option is to cut pigeon holes in the block wall and shove the floor joist in the holes so they are sitting on the wall instead of hanging on them.
Better than sticking some kind of anchor into a hollow CMU !

You could also drill through and put a threaded rod and plate on the outside to hold the ledger.
 

JoeMcGov

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Sep 8, 2018
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Birmingham, Alabama
Me? I would just run traditional 2X4 stud walls and then put your 2nd floor joists on top of them. This does assume you can loose the approx. 8" of room width that two stud walls would take up.
 

K'ledgeBldr

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Aug 22, 2011
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Johns Creek, GA
Can I securely hang joist on a CMU wall? I have an room 20x70 with 17' ceilings Id like to separate into 2 levels. I could stud wall inside and set the joist but is there an option to hang them from the wall?



Why F- with the wall and possibly destroy some integrity? Frame a supporting wall, know its framed to support the load, and call it a day!
 

readhead

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Dec 8, 2012
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Durango, Co.
As a steel erector we bolt structural steel to CMU often. Yes there is an engineer involved but it is a common construction practice used everyday.
 
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